Chemistry of Natural Compounds, Vol. 41, No. 1, 2005
B R I E F C O M M U N I C A T I O N S
PREPARATIVE SYNTHESIS OF VANILLIN AND VANILLAL
ESTERS OF SEVERAL CARBOXYLIC ACIDS
E. A. Dikusar and N. G. Kozlov
UDC 547.362
The natural plant aldehydophenols vanillin (4-hydroxy-3-methoxybnzaldehyde) (1a) and its close homolog vanillal
(4-hydroxy-3-ethoxybenzaldehyde) (1b) are widely used in the food and perfume industries [1, 2].
Our goal was to prepare new derivatives of the natural compounds as esters of 1a and 1b with several aromatic and
functionally substituted alkylcarboxylic acids (3a-u and 4a-e). The esters of 3a-u and 4a-e were synthesized using a method
that consists of reacting 1a or 1b with the corresponding acyl chlorides of the aromatic and functionally substituted
alkylcarboxylic acids (2) in absolute CH Cl with added pyridine. Acyl chlorides of the following acids (2) were used in the
2
2
ester synthesis: capric, stearic, acrylic, methacylic, oleic, benzoic, -toluic, phenylacetic, 2-phenylbutyric, cinnamic,
p
2-( -toluyloxy)propionic, succinic, -chlorobenzoic, -chlorobenzoic, , -dichlorobenzoic, , -dichlorophenyoxyacetic,
o p o p
p
o
p
bromoacetic, 1,2-dibromohydrocinnamic, -bromobenzoic, -nitrobenzoic, and -nitrobenzoic. This reaction converted the
p
m
p
starting phenols 1a and 1b into the corresponding esters 3a-u and 4a-e in yields of 80-90%.
CHO
RO
OC(O)R1
3a - u, 4a - e
3a - u: R = CH3; 4a - e: R = CH2-CH3; 3a: R1 = (CH2)8CH3; 3b: (CH2)16CH3; 3c: CH=CH2;
3d: C(CH3)=CH2; 3e: cis-(CH2)7CH=CH(CH2)7CH3; 3f: C6H5; 3g: n-C6H4CH3; 3h: CH2C6H5;
3i: CH2CH(CH3)C6H5; 3j: trans-CH=CHC6H5; 3k: n-(CH2)2OC6H4CH3; 3l: ½-(CH2)2-;
3m: o-C6H4Cl; 3n: n-C6H4Cl; 3o: o, n-C6H3Cl2; 3p: o, n-CH2OC6H3Cl2; 3q: CH2Br;
3r: CHBrCHBrC6H5; 3s: n-C6H4Br; 3t: m-C6H4NO2; 3u: n-C6H4NO2; 4a: R1 = C6H5;
4b: n-C6H4CH3; 4c: ½-(CH2)2-; 4d: o-C6H4Cl; 4e: n-C6H4Cl
Aromatic compounds 3a-u and 4a-e contain aldehyde, ester, and methoxy or ethoxy groups in addition to several
substituents associated with the structures of the starting carboxylic acid acyl chlorides (2). This enables them to be used as
synthons for further chemical trnasformations. Thepreparedestersare expected tobe promising for studying their antimicrobial
and radioprotector activities [3, 4].
The structures of the synthesized esters were confirmed by elemental analysis, cryoscopic molecular-weight
determination, and PMR, IR, and UV spectra. The purity of the prepared compounds according to PMR spectroscopy was
98 ± 1%.
Vanillin and Vanillal Esters 3a-u and 4a-e (general method). A solution of vanillin or vanillal (1a or 1b, 0.2 mol)
in absolute CH Cl (500 mL) was treated with absolute pyridine (0.25 mol) and in small portions with stirring and shaking with
2
2
the appropriate carboxylic acid acyl chloride (2, 0.2 mol, 0.1 mol for succinic acid). The reaction mixture was boiled for 1 h.
Institute of Physical Organic Chemistry, National Academyof Sciences of Belarus, 220072, Minsk, ul. Surganova, 13,
e-mail: loc@ifoch.bas-net.by. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 74-75, January-February, 2005.
Original article submitted August 2, 2004.
0009-3130/05/4101-0091 ©2005 Springer Science+Business Media, Inc.
91